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Magnetron-Sputtered Hard Nanostructured TiAIN Coatings Strategic Approach toward Potential Improvement
Published in Sivashankar Krishnamoorthy, Krzysztof Iniewski, Nanomaterials, 2017
Vishal Khetan, Nathalie Valle, Marie Paule Delplancke, Patrick Choquet
Along with Al content, hardness is also associated with the amount of residual stress in the film, which is modified due to Al content and the deposition parameters involved for a particular deposition technique. Though compressive residual stresses are desirable to some extent in retarding the crack propagation and in improving the fracture toughness of the coating, too high of a compressive stress causes poor adhesion of the film to the substrate [30]. The TiAlN coatings have been demonstrated to have a lower internal stress in the range of 4.5–5.2 GPa combined with a microhard-ness as high as 32.4 GPa (3300 HK) [30]. Therefore, TiAlN coating is preferred for wear-resistant applications over a TiN coating considering the mechanical properties exhibited by them.
Influence of substrate bias on machining performance of TiAlN-coated drill bits
Published in Materials and Manufacturing Processes, 2023
Nitin Tandekar, Pooja Miryalkar, L. Rama Krishna, Krishna Valleti
TiAlN coating offers excellent mechanical properties and oxidation resistance to meet the industrial demand for superior wear resistance of cutting tools.[12] The high-temperature resistance (~800°C), stemming from the presence of the Al2O3 passive layer and age hardening caused by spinodal decomposition,[13] overcomes the relatively poor thermal stability (~500°C) of conventional TiN and TiCN coatings.[14] These coating properties become even more critical in the case of the machining of difficult-to-cut materials (Nickel-based superalloys). The reasons are rapid temperature increase and resultant accelerated tool wear during cutting operations.[15] In general, the coating thickness, deposition conditions, and the selection of the machining parameters govern the performance of coated cutting tools.[16,17] Among coating deposition conditions, the substrate bias is an important parameter capable of affecting the coating deposition rate, crystallographic texture, and induced residual stress to a significant extent.[18,19]
Sliding wear performance of TiAl-based nitride coatings deposited on ADI by cathodic arc deposition and plasma based ion implantation and deposition
Published in Tribology - Materials, Surfaces & Interfaces, 2022
Diego Alejandro Colombo, Juan Pablo Quintana, Alejo Daniel Mandri, Adriana Beatriz Márquez, Ricardo César Dommarco
On the other hand, binary nitride coatings, such as TiN, can be alloyed with a third element, such as Al, to improve the properties of the coating [22–26]. Commercial TiAlN coatings have been widely used on tool steels due to their higher temperature resistance compared to TiN, as well as slightly higher hardness especially at high temperature. However, the performance of Ti1-xAlxN coatings depends strongly on their crystal structure which changes from cubic to hexagonal at an Al content x = 0.6 and causes a decrease in hardness and wear resistance [27–30]. The authors of the present work compared the wear behaviour, under lubricated rolling contact conditions, of ADI coated with TiN and TiAlN films deposited by CAD and by PBIID [31–33]. It was found that, under the deposition conditions used, TiN and TiAlN coatings grew with a cubic-NaCl type structure. In addition, TiN coatings deposited by CAD and by PBIID improved the rolling contact fatigue (RCF) resistance of ADI, while TiAlN coatings deposited by CAD did not produce significant changes with respect to uncoated ADI. Hsu et al. studied the response to erosion and corrosion of TiN and TiAlN coatings synthesized by CAD on ADI substrates. They reported that the coatings improved the erosion and corrosion resistance of the surfaces compared to uncoated ADI [19]. However, no work related to the sliding wear properties of TiAlN coatings on ADI has been found.
Correlation between the Al content and corrosion resistance of TiAlN coatings applied using a PACVD technique
Published in Journal of Asian Ceramic Societies, 2020
H. Elmkhah, A. Fattah-alhosseini, K. Babaei, A. Abdollah-Zadeh, F. Mahboubi
Figure 5 shows micro-hardness values for TiAlN coatings in different AlCl3/TiCl4 ratios, TiN coating, and an untreated specimen. For hardness evaluation, the suitable force (25 gr) was used depending on the thickness of the coating. Figure 4(b,d,e) shows that the thickness of the TiAlN(2) coating is about 3 µm. The results indicate that TiAlN coatings are significantly harder than the TiN nanostructured coating due to a solid solution of Al in the TiN coating [12]. But in the TiAlN samples, the hardness value verifies the different precursor ratios. There are some main effects to point out: (i) an interplanar spacing effect, (ii) a grain size effect and (iii) a chlorine content effect. Based on this investigation, effects (i) and (ii) enhance the hardness of the TiAlN nanostructured coatings but effect (iii) diminishes the properties. In the TiAlN(3) sample, effect (iii) is the predominant effect related to hardness.